In the European lands of the Ottoman Empire, the term hajduk was used to describe bandits and brigands of the Balkans, while in Central Europe for the West Slavs, Hungarians, and Germans it was used to refer to outlaws who protected Christians against provocative actions by the Ottomans. In the 17th century they were firmly established in the Ottoman Balkans, related to increased taxes, Christian victories against the Ottomans, and general security decline. Hajduk bands predominantly numbered one hundred men each, with a firm hierarchy under one leader. They targeted Ottoman representatives and rich people, mainly rich Turks, for plunder or punishment to oppressive Ottomans, or revenge or a combination of all.[1]

In Balkan folkloric tradition, the hajduk (hajduci or haiduci in the plural) is a romanticised hero figure who steals from, and leads his fighters into battle against, the Ottoman or Habsburg authorities. They are comparable to the English legend of Robin Hood and his merry men, who stole from the rich (which as in the case of the hajduci happened to be also foreign occupants) and gave to the poor, while defying seemingly unjust laws and authority.

The hajduci of the 17th, 18th and 19th centuries commonly were as much guerrilla fighters against the Ottoman rule as they were bandits and highwaymen who preyed not only on Ottomans and their local representatives, but also on local merchants and travelers. As such, the term could also refer to any robber and carry a negative connotation.[2][3]

The etymology of the word "hajduk" is unclear. One theory is that hajduk was derived from the Turkish word haidut or haydut, which was originally used by the Ottomans to refer to Hungarian and Polish-Lithuanian Commonwealth infantry soldiers. Another theory suggests that the word comes from the Hungarianhajtó or "hajdó" (plural hajtók or "hajdók"), meaning a (cattle) drover. [4] Indeed, these two theories do not necessarily contradict each other, as the Balkan word is said to be derived from the Turkish word haiduk or hayduk (bandit).[2][3][5]

Other spellings in English include ajduk, haydut, haiduk, haiduc, hayduck, hayduk.

In 1604–1606, István Bocskay, Lord of Bihar, led an insurrection against the HabsburgEmperor, whose army had recently occupied Transylvania and begun a reign of terror. The bulk of Bocskay's army was composed of serfs who had either fled from the war and the Habsburg drive toward Catholic conversion, or been discharged from the Imperial Army. These peasants, freelance soldiers, were known as the hajduk. As a reward for their service, Bocskay emancipated the hajduk from the jurisdiction of their lords, granted them land, and guaranteed them rights to own property and to personal freedom. The emancipated hajduk constituted a new "warrior estate" within Hungarian feudal society. Many of the settlements created at this time still bear the prefix Hajdú such as Hajdúbagos, Hajdúböszörmény, Hajdúdorog, Hajdúhadház, Hajdúnánás, Hajdúsámson, Hajdúszoboszló, Hajdúszovát, Hajdúvid etc., and the whole area is called Hajdúság (Land of the Hajduk) (see Hajdú County).

The word hajduk was initially a colloquial term for a style of footsoldier, Hungarian or Turco-Balkan in inspiration, that formed the backbone of the Polish infantry arm from the 1570s until about the 1630s. Unusually for this period, Polish-Lithuanian hajduks wore uniforms, typically of grey-blue woolen cloth, with red collar and cuffs. Their principal weapon was a small calibre matchlock firearm, known as an arquebus. For close combat they also carried a heavy variety of sabre, capable of hacking off the heads of enemy pikes and polearms. Contrary to popular opinion, the small axe they often wore tucked in their belt (not to be confused with the huge half-moon shaped berdysz axe, which was seldom carried by hajduks) was not a combat weapon, but rather was intended for cutting wood.

In the mid-17th century hajduk-style infantry largely fell out of fashion in Poland-Lithuania, and were replaced by musket-armed infantry of Western style. However, commanders or hetmans of the Polish-Lithuanian Commonwealth continued to maintain their own liveried bodyguards of hajduks, well into the 18th century as something of a throwback to the past, even though they were now rarely used as field troops. In imitation of these bodyguards, in the 18th century wealthy members of the szlachta hired liveried domestic servants who they called hajduks, thereby creating the meaning of the term 'hajduk' as it is generally understood in modern Polish.[6]

In the early 1970s, after the publication of the now classic sociological studies Primitive Rebels and Bandits by historian Eric Hobsbawm, hajduks started appearing in western social and anthropological literature. Hobsbawm invented the term "social bandit" to describe outlaws who operate on the edges of rural societies by fighting against authorities and sometimes helping the ordinary people. There has always been a degree of fluidity in their status, whereby, as described by John Koliopoulos in his study of Greekklephts, Brigands with a Cause, brigands would sometimes change sides and start acting on behalf of the authorities to preserve peace and suppress banditry, and vice versa.

From the early 1980s, sociological studies started narrating the stories of hajduks, klephts, bandits, brigands, outlaws, rebels, and pirates in all parts of the planet, from Australia to republican China, the Balkans, the AmericanWild West, Cuba and Mexico.